The exon starting at position 136,150,952 on chromosome 5 (exon 3 in Orai2-001 transcript and exon 5 in the Orai2-003 transcripit) was flanked by loxP sites. An FRT-flanked YFP-reporter (En2 splice acceptor, 2A self-cleavage protein, YFP coding sequence)-STOP-neomycin resistance cassette was inserted upstream of the floxed region. Flp-mediated recombination removed the YFP reporter and neo cassette and cre-mediated recombination deleted exon 3/exon5. qPCR confirmed absence of transcripts in peritoneal mast cells. (J:278536)